Dual Timer. XR-L556 Datasheet

XR-L556 Timer. Datasheet pdf. Equivalent


Exar XR-L556
XR-L556
Micropower Dual Timer
GENERAL DESCRIPTION
The XR-L556 dual timer contains two independent mi-
cropower timer sections on a monolithic chip. It is a di-
rect replacement for the conventional 556-type dual
timers, for applications requiring very low power dissi-
pation. Each section of the XR-L556 dual timer is equiv-
alent to Exar's XR-L555 micropower timer. The circuit
dissipates only 1/15th of the stand-by power of conven-
tional dual timers and can operate down to 2.5 volts
without sacrificing such key features as timing accu-
racy and stability. At 5 volt operation, typical power dis-
sipation of the dual-timer circuit is less than 2 mW; and
it can operate in excess of 500 hours with only two 300
mA-Hr NiCd batteries.
The two timer sections of the circuit have separate con-
trols and outputs, but share common supply and
ground terminals. Each output can source up to 100
mA of output current or drive TTL circuits.
FEATURES
Replaces two XR-L555 Micropower Timers
Pin Compatible with Standard 556-Type Dual Timer
Less than 1 mW Power Dissipation per Section (VCC =
5V)
Timing from Microseconds to Minutes
Over 500-Hour Operation with 2 NiCd Batteries Low
Voltage Operation (VCC = 2.5V)
Operates in Both Monostable and Astable Modes
CMOS TTL and DTL Compatible Outputs
Introduces No Switching Transients
APPLICATIONS
Battery Operated Timing
Micropower Clock Generator
Pulse Shaping and Detection
Micropower PLL Design
Power-On Reset Controller
Micropower Oscillator
Sequential Timing
Pulse-Width Modulation
Appliance Timing
Remote-Control Sequencer
ABSOLUTE MAXIMUM RATINGS
Power Supply
Power Dissipation
Ceramic Dual-In-Line
Derate above TA = 25°C
Plastic Dual-In-Line
Derate above TA = 25°C
Storage Temperature Range
18V
750 mW
6 mW/oC
625 mW
5 mW/oC
-65°C to + 150°C
FUNCTIONAL BLOCK DIAGRAM
DISCH"RCI
THRESHOLD
CONTROL
VOLTAGE
RESn
OUTPUT
TRIGGER
GROUND
ORDERING INFORMATION
Part Number
XR-L556 M
XR-L556 CN
XR-L556 CP
Package
Ceramic
Ceramic
Plastic
Vee
OISCII"RG£
fllRUIiOLD
COlnnOL
VOLTAG£
nnn
OUtPUT
lRIGGtR
Operating Temperature
- 55°C to + 125°C
O°C to + 70°C
O°C to + 70°C
SYSTEM DESCRIPTION
The XR-L556 is a micropower version of the industry
standard XR-556 timing circuit, capable of both
monostable and astable operation with timing intervals
ranging from low microseconds up through several
hours. Timing is independent of supply voltage, which
may range from 2.5 V to 15 V. The output stage can
source 100 mA. Each timer section is fully independent
and similar to the XR-L555.
In the monostable (one shot) mode, timing is deter-
mined by one resistor and capacitor. Astable operation
(oscillation) requires an additional resistor, which con-
trols duty cycle. An internal resistive divider provides a
reference voltage of 2/3 VCC, which produces a timing
interval of 1.1 RC. As the reference is related to VCC,
the interval is independent of supply voltage; however,
for maximum accuracy, the user should ensure VCC
does not vary during timing.
The output of the XR-L556 is high during the timing in-
terval. It is triggered and reset on falling waveforms.
The control voltage inputs (Pins 3 and 11) may serve as
pulse width modulation points.
5-85


XR-L556 Datasheet
Recommendation XR-L556 Datasheet
Part XR-L556
Description Micropower Dual Timer
Feature XR-L556; XR-L556 Micropower Dual Timer GENERAL DESCRIPTION The XR-L556 dual timer contains two independent.
Manufacture Exar
Datasheet
Download XR-L556 Datasheet




Exar XR-L556
XR·L556
ELELTRICAL CHARACTERISTICS
Test Conditions: (TA = 25 DDC, VCC = + 5V, unless otherwise specified)
XR-L556M
XR-L556C
PARAMETERS
Supply Voltage
Supply Current
(Each Timer Section)
Total Supply Current
(Soth Timer Sections)
Timing Error
Initial Accuracy
Drift with Temperature
Drift with Supply Voltage
Threshold Voltage
Trigger Voltage
Trigger Current
Reset Voltage
Reset Curerent
Threshold Current
Control Voltage Level
Output Voltage Drop (Low)
Output Voltage Drop (High)
Rise Time of Output
Fall Time of Output
Discharge Transistor
Leakage
MIN
2.5
1.45
4.8
0.4
2.90
9.6
3.0
13
TYP MAX
15
150 300
300 600
0.5
50
0.5
2/3
1.67
5.0
20
0.7
10
10
3.33
10.0
0.1
200
1.9
5.2
1.0
50
3.80
10.4
0.3
3.3
13.3
12.5
200
100
0.1
MIN
2.7
0.4
2.60
9.0
2.75
12.75
TYP MAX
15
200 500
400 1000
1.0
50
0.5
2/3
1.67
5.0
20
0.7
10
20
3.33
10.0
0.15
1.0
100
4.00
11.0
0.35
3.3
13.3
12.5
200
100
0.1
UNITS
V
p,A
p,A
%
ppm/DC
%IV
X VCC
V
V
nA
V
p,A
nA
V
V
V
V
V
V
nsec
nsec
p,A
CONDITION
Low State Output
VCC = 5V, RL = 00
RA, RS = 1 KO to 100 KO
C = 0.1 p,F
ODC ~ TA ~ 70 DC
Monostable Operation
VCC = 5V
VCC = 15V
VCC = 5V
VCC = 15V
Isink = 1.5 mA
Isource = 10mA
VCC = 5V
VCC = 15V
Isource = 100 mA
VCC = 15V
OUTPUT
,.----...----...---oVCC
RESET
.. 14
112 OF XR L~~6 t - - c r - - - ,
In ICONTROL
T~Rl-GG-ER-----TR<IG~GE-R~__~~
INPUT
-
C
Figure 1. Monostable (One-Shot) Circuit
, . - - - - _ -__--Qv.
OUTPUT
RL RESET
14
DISCHARGE
112 OF XR 5~6
CONTROL
INPUT
CONTROL
f.~ DUTYCYClE _ _ _R_S _
IRA + 2RalC
RA + 2RS
Figure 2. Astable (Free-Running) Circuit
R8
TRIGGER
THRESHOLD
5-86



Exar XR-L556
XR·L556
GENERAL CHARACTERISTICS
~ T~ ~250~800
720
640 -
~
....
560
~ 480
-
=
V
A
,.JC-2~OC
,A
/'
.,.,1/
a:
~ 400
u
/' V~ . Y
... V t.,.....-V
~ 320
~ 240
II
V""" TA =+75 'c - I--
~ l7
VI160
80
o
4 6 8 10 12 14 16 18 20
SUPPLY VOLTAGE, V CC (VOLTSI
CHARACTERISTIC CURVES
1200
1100
iii
c:
1000
i.a...
3:
900
800
I0
TA = +25 C
/I
I
II
1/Vee· 2.5V/
...w 700
til
~ 600
:;; 500
::;J; 400
V
J
/I
Z
:E
300
-200
100
"'---
7
./
V
f vcc = 5V-
II
0.1 0.2 0.3 0.4
LOWEST VOLTAGE LEVEL OF
TRIGGER PULSE (X V cel
1200
, '0-,- /1- l JI~ 1000
Vec
-5V_
I
f-TA
.:s~
----~I
>
800 -TA = .25 e
a
z
600 L-- I---
...... ~
'-"";:::: ~ __ 25OC_
;0::
"oCt 400
;t
0
~ 200
0.1 0.2 0.3
LOWEST TRIGGER VOLTAGE
LEVEL (X vccl
0.4
Figure 3. Total Supply Current as a
Function of Supply Voltage
MONOSTABLE OPERATION
Figure 4. Minimum Pulse-Width
Required for Triggering
Figure 5. Propagation Delay as a
Function of Voltage Level of
Trigger Pulse
+4
~ +3
a:
~ +2
~
t:l +1
Z
:E 0
;::
~ -1
~ -2
::;
~ -3
z
-4
o
1V
VV /
V
V
/
II
10 15 20
SUPPLY VOL TAGE V CC (VOLTSI
~2
c:
~
---t:l
Z
:E
I'...
;:: 0
8
I--
N
:::; -1
:<;;t
c:
~ -2
'".......
-3
-25
o
25°C
50
TEMPERATURE (oCI
75
2.0
....
>'
~ 1.5
a
w:;;
;:: 1.0
8
:N::;
<t 0.5
:;;
oaz: o
o
/
V
J
/
.11
VI
I
I
0.2 0.4 0.6 0.8 1.0
CONTROL VOLTAGE AS FRACTION OF ~cc
Figure 6. Typical Timing
Accuracy as a Function of
Supply Voltage
ASTABLE OPERATION
Figure 7. Typical Timing
Accuracy as a Function of
Temperature
(VCC =5V, RA = IOOKr2, C =O.OIJLF)
Figure 8. Normalized Time
Delay as a Function of
Con trol Voltage
+2
LJ J-1:1ta;:: +1
Jo
>u
I~ IR '= R
AB
~
RA =R B =lOOK
~
:oJ
IJ'/
Ifw -1
:f
o
~ -2
:::;
oCt
~ -3
o
Z
-4
TA = 25°C
iI
10 15 20
SUPPL Y VOL TAGE, VCC (VOL TSI
_ +1.5
~
ta;:: +1
" ,~a
>
~ +0.5
:J
~
f-.
:f
a
~ -0.5
:::;
---- .......... ..........
oCt
~ -1
oz
Vc-jc = 5V,
-1.5
-25 o 25 50 75
TEMPERATURE tel
2.0
>.
u
~
":J 1.5
8
:f
'"8 1.0
:N::;
"-:o:C;t 0.5
"-
"-1""'-.
I
c: I
0z I
0.2 0.4 0.6 0.8 1.0
CONTROL VOLTAGE AS FRACTION OF Vcc
Figure 9. Typical Frequency
Stability as a Function of
Supply VoItage
Figure 10. Typical Frequency
Stability as a Function of
Temperature
(RA =RB =IOKr2. C =O.IJ1F)
Figure 11. Normalized Frequency
of Oscillation as a Function of
Control Voltage
II
5-87







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